3D Crystal Structure of the Photosystem II Core

Photooxidation Pathway of Chlorophyll Z in Photosystem II as Studied by Fourier Transform Infrared Spectroscopy

“…It is generally thought that Chl Z is oxidized via Car (4,6,7,23,25,26,38,39), based on the observations that Car + is trapped to a larger extent than Chl Z at lower temperatures (21,23,26) and the trapped Car + is mostly replaced with Chl Z + by warming up the sample (23,25,38,39). This electron-transfer pathway (P680 + r Car r Chl Z ) is consistent with the relative positions of these pigments on the D2 side in the X-ray structure of all three groups (10)(11)(12)(13)30) and on the D1 side in the new structure of T. elongatus by Loll et al (13); the Car molecules are positioned between P680 and Chl Z . This pathway, however, was inconvenient for the oxidation of Chl Z (D1) in the context of the X-ray structure of T. Vulcanus (30) and the previous structures of T. elongatus (10,11), in which no Car was found on the D1 side.…”

“…There are also two redox-active Car molecules in the PSII reaction center (4)(5)(6)(7)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29). The positions of these Car molecules, however, have not yet been definitely determined by X-ray crystallography (10)(11)(12)(13)30). Kamiya and Shen (12,30) showed that both Car molecules are attached to the D2 subunit in their X-ray crystal structure of the PSII core complex from Thermosynechococcus Vulcanus at 3.7 Å resolution.…”

“…The positions of these Car molecules, however, have not yet been definitely determined by X-ray crystallography (10)(11)(12)(13)30). Kamiya and Shen (12,30) showed that both Car molecules are attached to the D2 subunit in their X-ray crystal structure of the PSII core complex from Thermosynechococcus Vulcanus at 3.7 Å resolution. On the other hand, in the crystal structures of Thermosynechococcus elongatus by Ferreira et al (3.5 Å resolution) (10) and Biesiadka et al (3.2 Å resolution) (11), only one Car was resolved on the D2 subunit.…”

“…Very recently, Loll et al (13) reported the 3.0 Å resolution structure of T. elongatus, in which another Car is attached to the D1 subunit near Chl Z (D1). Thus, all of these structures [for T. Vulcanus, the revised one (30)] showed a common all-trans Car near Chl Z (D2), whereas the position of the other Car is still controversial. Only a single Cytb559 on the D2 side was found in the X-ray structures of PSII in both T. Vulcanus and T. elongatus (10)(11)(12)(13).…”

Structural and functional aspects of the MSP (PsbO) and study of its differences in thermophilic versus mesophilic organisms

“…Each monomer has one reaction center, and over 20 individual polypeptide subunits. The subunits can be classed as intrinsic, those embedded in the thylakoid membrane, or extrinsic, proteins attached to the lumenal surface of the intrinsic subunits (Barber and Iwata 2005;Shen and Kamiya 2005;Witt 2005). The D1 and D2 intrinsic subunits form the center of the PSII monomer.…”